Intramedullary implant, system, and method for inserting an implant into a bone

ABSTRACT

An intramedullary implant system, and method for placement within a bone system are provided by the invention. The implant includes a body with at least one pair of beams arranged about a longitudinal axis of the body. The beams are each fixed to the body and each have an end. The end of one of the beams of a pair is releasably coupled to the other beam of the pair by a k-wire from one end of which extends a flexible tail. The beams are each deflectable between (i) a coupled and biased position for insertion of the beams into a respective bone, and (ii) an uncoupled position for gripping bone. The beams of each pair in the uncoupled position being arranged so as to compressively engage the bone.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of co-pendingU.S. application Ser. No. 14/179,172, filed on Feb. 12, 2014, theentirety of which is incorporated by reference herein.

FIELD OF DISCLOSURE

The disclosed device, system, and method relate to implants and, moreparticularly to implants for installation in an appendage for treating avariety of skeletal maladies including hammer toe.

BACKGROUND OF THE INVENTION

Hammer toe is a deformity of the toe that affects the alignment of thebones adjacent to the proximal interphalangeal (PIP) joint. Hammer toecan cause pain and can lead to difficulty in walking or wearing shoes. Ahammer toe can often result in an open sore or wound on the foot. Insome instances, surgery may be required to correct the deformity byfusing one or both of the PIP and distal interphalangeal (DIP) joints.

The most common corrective surgery includes the placement of a pin orrod in the distal, middle, and proximal phalanxes of the foot to fusethe PIP and DIP joints. The pin or rod is cut at the tip of the toe,externally of the body. A plastic or polymeric ball is placed over theexposed end of the rod, which remains in the foot of the patient untilthe PIP and/or DIP joints are fused in approximately 6 to 12 weeks. Thisconventional treatment has several drawbacks such as preventing thepatient from wearing closed toe shoes while the rod or pin is in place,and the plastic or polymeric ball may snag a bed sheet or other objectdue to it extending from the tip of the toe resulting in substantialpain for the patient.

Another conventional implant includes a pair of threaded members thatare disposed within adjacent bones of a patient's foot. The implants arethen coupled to one another through male-female connection mechanism,which is difficult to install in situ and has a tendency to separate.

Yet another conventional implant has a body including an oval head and apair of feet, which are initially compressed. The implant is formed fromnitinol and is refrigerated until it is ready to be installed. The headand feet of the implant expand due to the rising temperature of theimplant to provide an outward force on the surrounding bone wheninstalled. However, the temperature sensitive material may result in theimplant deploying or expanding prior to being installed, which requiresa new implant to be used.

Accordingly, an improved intramedullary implant for treating hammer toeand other maladies of the skeletal system is desirable that providesactive compression across a joint and maintains compression thereafterso as to greatly increase the fusion rate. The implant should beinsertable with minimal disruption to the DIP joint while optimizingcompression and fixation at the PIP joint. Such an improved implantcould find efficacy in Hammertoe surgery.

SUMMARY OF THE INVENTION

An intramedullary implant system is provided that includes a body fromeach opposite end of which project a pair of beams arranged about alongitudinal axis of the body. The beams are each fixed to the body andeach has a coupling latch with a bore so that the coupling latch of eachof the beams of a pair may be releasably coupled to the other beam ofthe pair of beams by a removable coupling rod. A flexible tail projectsfrom one end of the removable coupling rod projects outwardly. Each ofthe pair of beams is movable between (i) a coupled and biased positionwherein the coupling rod is located in each bore of each latch so thatthe implant may be inserted into a respective bone with at least aportion of the flexible tail protruding from the implant, and (ii) anuncoupled position for internally gripping the respective bone. Thebeams of each pair in the uncoupled position diverge away from thelongitudinal axis of the body wherein an outer surface of each beam isadapted to form a compressive engagement with the respective bone whendisposed in the uncoupled position.

In another embodiment of a intramedullary implant system, a body has anend from which project a pair of beams arranged about a longitudinalaxis of the body. The beams are each fixed to the body with the end ofone of the beams being releasably coupled to the other beam of the pairby a removable coupling rod. A flexible tail projects from one end ofthe coupling rod. The beams are each deflectable between (i) a coupledand biased position for insertion of the beams into a respective boneand with at least a portion of the flexible tail positioned within abone, and (ii) an uncoupled position for gripping the respective bone,the pair of beams in the uncoupled position being arranged so as to forma compressive engagement with the respective bone.

In a further embodiment of an intramedullary implant system a firstk-wire is provided from one end of which extends a flexible tail. A bodyis provided from opposite ends of which project at least one pair ofbeams arranged about a longitudinal axis of the body. The beams are eachfixed to the body and each have a coupling latch with a bore so that thecoupling latch of each of the beams of a pair may be releasably coupledto the other beam of the pair of beams by the k-wire such that each ofthe pair of beams is movable between (i) a coupled and biased positionwherein the k-wire is located in each bore of each latch so that theimplant may be inserted into a respective bone and (ii) an uncoupledposition wherein the k-wire is removed from each bore of each latch sothat the beams of each pair diverge away from the longitudinal axis ofthe body wherein an outer surface of each beam is adapted to form acompressive engagement with the respective bone when disposed in theuncoupled position.

A method for implanting a device within a bone is provided that includesopening and debriding a target bone system. A canal is formed throughthe target bone system, and a k-wire is provided that has a flexibletail extending from one end. An implant is also provided that includes abody from opposite ends of which project at least one pair of beamsarranged about a longitudinal axis of the body wherein the body definesa passageway along the longitudinal axis. The beams are each fixed tothe body and each has a coupling latch with a bore. The latch of eachbeam is releasably coupled to one another by inserting the k-wire intothe latch bores thereby biasing the beams. The implant and k-wire areinserted into the canal along with the flexible tail, often protrudingfrom the patient's body. By pulling upon the flexible tail so as todecouple and remove the k-wire from the latches, the beams are therebydecoupled and released from their biased state so that a portion of eachbeam engages the surface of the surrounding bone that defines the canal.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the invention will be morefully disclosed in, or rendered obvious by the following detaileddescription of preferred embodiments of the invention, which are to beconsidered together with the accompanying drawings wherein like numbersrefer to like parts and further wherein:

FIG. 1 is a perspective view of an intramedullary implant formed inaccordance with one embodiment of the invention;

FIG. 2 is a top plan view of the implant shown in FIG. 1;

FIG. 3 is a top plan view of the implant shown in FIGS. 1 and 2, andwith a K-wire coupled to the implant;

FIG. 4 is a top plan view, partially in phantom, illustrating the changein length of the beams as a result of decoupled bending;

FIG. 5 is a perspective view of the distal, middle, and proximalphalanxes with a K-wire installed, and with the soft tissues removed forclarity of illustration;

FIG. 5A is a further perspective view of the distal, middle, andproximal phalanxes without a K-wire installed, and with the soft tissuesremoved for clarity of illustration;

FIG. 6 is a side view of the distal, middle, and proximal phalanxesshown in FIGS. 5 and 5A;

FIG. 7 is a side view of the distal, middle, and proximal phalanxes withan implant formed in accordance with one embodiment of the inventioninstalled in the proximal end of a middle phalanx, and with the softtissues removed for clarity of illustration;

FIG. 8 is a top plan view showing an implant fully installed between theproximal and middle phalanxes, just prior to removal of the k-wire;

FIG. 9 is a top plan view showing an implant fully installed between theproximal and middle phalanxes, with the K-wire removed and decoupledfrom the proximal and distal pair of beams, and illustrating an implantfully installed within the bones;

FIG. 6A is a top plan view of a distal and middle phalanx showinginitial insertion of an implant device and system in accordance with analternative method of installation;

FIG. 7A is a top plan view, similar to FIG. 6A, showing further progressof the implant system through a canal broached within the bones;

FIG. 7B is a side view, partially in phantom showing progress of theimplant system, including a k-wire with a flexible tail, through a canalbroached within the bones;

FIG. 8A is a top plan view, similar to FIGS. 6A and 7A, showing a K-wirepartially removed and decoupled from a distal pair of beams, andillustrating the compressive engagement of the beams against theinternal surfaces of the bone;

FIG. 8B is a top plan view, similar to FIG. 7B, showing an implantcoupled by a K-wire with a flexible tail prior to removal and decouplingfrom a distal pair of beams;

FIG. 9A is a top plan view, similar to FIGS. 6A, 7A, and 8A, showing theimplant fully installed with the K-wire removed and decoupled from aproximal pair of beams, and illustrating an implant fully installedwithin the bones;

FIG. 9B is a perspective view of an implant formed in accordance withthe invention, showing an alternative K-wire having a flexible tailinstalled and coupling the beams of the implant;

FIG. 9C is a side elevational view of the implant and k-wire shown inFIG. 9B, with the implant shown in cross-section for clarity ofillustration perspective view of an implant formed in accordance withthe invention, showing an alternative K-wire having a flexible tailinstalled and coupling the beams of the implant;

FIG. 9D is a top plan view, similar to FIGS. 7B and 8B, showing a K-wirewith a flexible tail partially removed and decoupled from a distal pairof beams, and illustrating the compressive engagement of the beamsagainst the internal surfaces of the bone;

FIG. 9E is a perspective view, partially in phantom, of a human footlocated within a shoe and illustrating one possible arrangement of aflexible tail and second k-wire after implantation of an implant formedin accordance with on embodiment of the invention;

FIG. 10 is a perspective view of the implant shown in FIGS. 11 and 12with the K-wire reinstalled through central canal to stabilizeneighboring joints (MTP);

FIG. 11 is a further perspective view of the implant shown in FIG. 12,with a K-wire removed;

FIG. 12 is a perspective view of an alternative embodiment of implantformed in accordance with the invention;

FIG. 13 is a top plan view of a further alternative embodiment of theinvention, showing a K-wire partially in phantom, installed and coupledto a single pair of beams;

FIG. 14 is a top plan view of the implant shown in FIG. 13, but with theK-wire removed and decoupled from the beams;

FIG. 15 is a top plan view, similar to FIG. 14, showing a K-wire priorto coupling with the implant;

FIG. 16 is a bottom plan view of the implant shown in FIG. 15, but fromthe reverse side so as to reveal grooves or channels formed in theimplant for receiving a coupling K-wire;

FIG. 17 is a top plan view, partially in phantom, showing a K-wirecoupled with the implant of FIGS. 15-16;

FIG. 18 is a further embodiment of implant formed in accordance with theinvention;

FIG. 19 is a cross-sectional view, similar to FIG. 18, but showing aK-wire coupled to the beams of the implant;

FIG. 20 is an end view of a further embodiment of implant formed inaccordance with the invention;

FIG. 21 is a side elevational view of the further embodiment shown inFIG. 20;

FIG. 22 is a cross-sectional view, taken along lines 22-22 in FIG. 21;

FIG. 23 is a perspective view of a further embodiment of the inventionshowing an implant having a curved cross-sectional profile;

FIG. 24 is a side elevational view of an angled implant embodiment ofthe invention;

FIG. 25 is a top plan view of the angled embodiment of the inventionshown in FIG. 24;

FIG. 26 is an end on, perspective view of the embodiment of implantshown in FIGS. 24 and 25;

FIG. 27 is a cross-sectional view taken along lines 27-27 of the angledembodiment shown in FIGS. 24-26;

FIG. 28 is a top plan view of yet a further embodiment of implantshowing a pair of beams disposed diagonally on the body of the implant;

FIG. 29 is top view similar to FIG. 28, showing the implant coupled to aK-wire in accordance with invention;

FIG. 30 is a top view of yet a further embodiment of implant showing apair of beams disposed on the same side of the body of the implant;

FIG. 31 is a top view similar to FIG. 30, showing the implant coupled toa K-wire in accordance with invention;

FIG. 32 is a perspective view of an embodiment formed in accordance withthe invention showing a single pair of beams coupled to a K-wire;

FIG. 33 is a cross-sectional view, taken along line 33-33 in FIG. 32;

FIG. 34 is a perspective exploded view of the alternative embodimentimplant of FIGS. 32 and 33, showing a therapeutic device prior tointerconnection with the implant;

FIG. 35 is a perspective view of the implant and therapeutic deviceshown in FIG. 34, after interconnection;

FIG. 36 is a cross-sectional view of the implant and therapeutic deviceinterconnected in FIG. 35;

FIG. 37 is a perspective view, similar to FIG. 34, showing a therapeuticdevice in the form of a bone anchor just prior to interconnection withthe implant;

FIG. 38 is a perspective view, similar to FIG. 35, showing bone anchorof FIG. 37 interconnected with the implant;

FIG. 39 is a cross-section view, similar to FIG. 36, but showing a boneanchor of FIGS. 37 and 38 interconnected with an implant formed inaccordance with the invention;

FIG. 40 is an exploded perspective view of an implant similar to thatshown in FIGS. 34 and 37, showing a suture anchor just prior tointerconnection with the implant;

FIG. 41 is a perspective view similar to FIG. 40 but showing the sutureanchor installed on the implant;

FIG. 42 is a cross-sectional view, taken along line 42-42 in FIG. 41,showing the suture anchor installed on the implant with suture threadedthrough a conduit defined to the middle of the body of the implant andalso showing a K-wire coupled to the single pair of beams;

FIG. 43 is a cross-sectional view similar to FIG. 42, with the K-wiredecoupled from the single pair of beams;

FIG. 44 is a perspective view of a further alternative embodiment of theinvention showing a bone screw interconnected with the implant of theinvention;

FIG. 45 is a cross-sectional view, taken along line 45-45 in FIG. 44,and also showing a K-wire coupled to a single pair of beams;

FIG. 46 is a cross-sectional view similar to FIG. 45, but showing thesingle pair of beams after decoupling from the K-wire;

FIG. 47 is another embodiment of implant similar to that shown in FIGS.34, 37, 40, and 44, showing a cannulated bone screw installed in theimplant with a K-wire located within the cannulated bone screw andcoupled to the single pair of beams;

FIG. 48 is a cross-sectional view, taken along line 48-48 in FIG. 47;and

FIG. 49 is a cross-sectional view similar to FIG. 48 but with the K-wireremoved from the cannulated bone screw and decoupled from the singlepair of beams.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

This description of preferred embodiments is intended to be read inconnection with the accompanying drawings, which are to be consideredpart of the entire written description. The drawing figures are notnecessarily to scale and certain features of the invention may be shownexaggerated in scale or in somewhat schematic form in the interest ofclarity and conciseness. In the description, relative terms such as“horizontal,” “vertical,” “up,” “down,” “top,” and “bottom” as well asderivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,”etc.) should be construed to refer to the orientation as then describedor as shown in the drawing figure under discussion. These relative termsare for convenience of description and normally are not intended torequire a particular orientation. Terms including “inwardly” versus“outwardly,” “longitudinal” versus “lateral,” and the like are to beinterpreted relative to one another or relative to an axis ofelongation, or an axis or center of rotation, as appropriate. Termsconcerning attachments and the like, such as “coupled” and “coupling”refer to a relationship wherein structures are secured or attached toone another either directly or indirectly, temporarily or permanently,through intervening structures, as well as both movable or rigidattachments or relationships, unless expressly described otherwise. Theterm “operatively coupled” is such an attachment or connection thatallows the pertinent structures to operate as intended by virtue of thatrelationship.

Referring to FIGS. 1-4, an implant 2 is provided that includes acannulated body 4, a distal pair of cantilevered beams 6, and a proximalpair of cantilevered beams 8. More particularly, cannulated body 4 oftencomprises an elongate bar having a distal end 14 and a proximal end 15.A through-bore 18 is often defined centrally through the bar alonglongitudinal axis 17 so as to define openings at distal end 14 andproximal end 15.

Distal pair of beams 6 comprise a superior beam 24 and an inferior beam26 arranged in spaced confronting relation to one another at distal end14 of cannulated body 4. In many of the embodiments of the invention,pairs of beams will be arranged symmetrically about longitudinal axis 17of body 4, often so as to be bisected by the axis. Superior beam 24 isfixed to distal end 14 of cannulated body 4, and in some embodiments, isformed integral with cannulated body 4. One or more barbs 30 a arelocated on an outer surface 31 of superior beam 24, often orientedtransversely across outer surface 31. A latch-plate 34 extends inwardly,toward inferior beam 26, from a free end of superior beam 24. A bore 36a is defined through latch-plate 34. Inferior beam 26 is fixed to distalend 14 of cannulated body 4, and in some embodiments, is formed integralwith cannulated body 4. One or more barbs 30 b are located on a distalouter surface 32 of inferior beam 26, often oriented transversely acrossouter surface 32. A latch-plate 38 extends inwardly, toward superiorbeam 24 and latch-plate 34, from a free end of inferior beam 26. A bore36 b is defined through latch-plate 38.

Distal pair of beams 6 are cantilevered to cannulated body 4 at distalend 14, i.e., supported or clamped at one end and capable of storingelastic energy when loaded or pre-loaded at the other end or along theirlength. When distal pair of beams 6 are loaded during normal use, theyeach deflect inwardly, toward one another. Advantageously, superior beam24 is greater in length than inferior beam 26 so that, when deflected toa optimally biased state, i.e., the beams are deflected so that adesirable amount of elastic energy is stored, with latch-plate 34 islocated in overlapping adjacent relation to latch-plate 38 with bore 36a and bore 36 b overlapping and communicating relation to one another(FIGS. 3-4). As a result, while distal pair of beams 6 are loaded bores36 a and 36 b will often be arranged in substantially coaxial relationto the open end of through-bore 18 at distal end 14 of cannulated body4.

Proximal pair of beams 8 comprise a superior beam 44 and an inferiorbeam 46 arranged in spaced confronting relation to one another atproximal end 15 of cannulated body 4. Superior beam 44 is fixed toproximal end 15 of cannulated body 4, and in some embodiments, is formedintegral with cannulated body 4. One or more barbs 50 a are located onan outer surface 51 of superior beam 44, often oriented transverselyacross outer surface 51. A latch-plate 54 extends inwardly, towardinferior beam 46, from a free end of superior beam 44. A bore 56 b isdefined through latch-plate 54. Inferior beam 46 is fixed to proximalend 15 of cannulated body 4, and in some embodiments, is formed integralwith cannulated body 4. One or more barbs 50 b are located on a distalouter surface 52 of inferior beam 46, often oriented transversely acrossouter surface 52. A latch-plate 58 extends inwardly, toward superiorbeam 44 and latch-plate 54, from a free end of inferior beam 46. A bore56 a is defined through latch-plate 58.

As with distal pair of beams 6, proximal pair of beams 8 are alsocantilevered to cannulated body 4, but at proximal end 15, i.e.,supported or clamped at one end and capable of storing elastic energywhen loaded or pre-loaded at the other end or along their length. Whenproximal pair of beams 8 are loaded during normal use, they each deflectinwardly, toward one another. Advantageously, superior beam 44 isgreater in length than inferior beam 46 so that, when deflected to aoptimally biased state, latch-plate 58 is located adjacent tolatch-plate 54 with bore 56 a and bore 56 b overlapping one another. Asa result, bores 56 a and 56 b often will be arranged in substantiallycoaxial relation to the open end of through-bore 18 at proximal end 15of cannulated body 4.

When cantilevered distal pair of beams 6 and proximal pair of beams 8move into their respective second partially biased state, they undergo aso-called “large deflection” in accordance with classical beam theory.In other words, the moment arm of each of superior beam 24,44 andinferior beam 26,46 changes as the loaded ends of the beams deflectinwardly toward one another. Referring to FIG. 4, it will be understoodby those skilled in the art that when distal pair of beams 6 andproximal pair of beams 8 are arranged in their optimally biased state,the distance β measured between their outer most barbs is at a maximum,but when cantilevered distal pair of beams 6 and proximal pair of beams8 are allowed to move into their respective second partially biasedstate, the distance θ measured between the outer most barbs is at aminimum. Thus, there is a differential in the length of the beams, δ,between their optimally biased state and their second partially biasedstate. This difference δ represents an available amount of compressiveengagement or “bite” of the barbs into the bone that defines broachedcanal D.

Implant 2 may be manufactured from conventional implant metal, such asstainless steel or titanium. In several preferred embodiments, however,the implants are manufactured out of shape memory materials (SMA) oralloys such as nickel titanium to enhance fixation. One example of suchan alloy is Nitinol sold by Memry Corporation of Menlo Park, Calif. Theimplants are preferably made of nitinol, a biocompatible, shape memorymetal alloy of titanium and nickel. The metal's properties at the highertemperature (austenite phase) are similar to those of titanium. Thetemperature at which the implants will undergo the shape transformationcan be controlled by the manufacturing process and the selection of theappropriate alloy composition. Nitinol has a very low corrosion rate andhas been used in a variety of medical implants, e.g., orthodonticappliances, stents, suture anchors, etc. Implant studies in animals haveshown minimal elevations of nickel in the tissues in contact with themetal; the levels of titanium are comparable to the lowest levels foundin tissues near titanium hip prostheses. In most embodiments of theinvention, the SMA is selected to have a temperature transformationrange such that the implant undergoes a transition from austenite tostress-induced martensite under the influence of deformation forces.Thus, when the distal and proximal beams of implant 2 are deflectedinwardly, toward one another and then released, they are already at atemperature such that they automatically attempt to reform to theiroriginal shape.

Referring to FIGS. 5-9A, implant 2 is prepared for use in correctivesurgery at the distal B, middle A, and proximal C phalanxes of the foot,as follows. Distal pair of beams 6 are loaded so that they each deflectinwardly, toward one another until latch-plate 38 is located adjacent tolatch-plate 34 with bore 36 a and bore 36 b overlapping one another.Likewise, proximal pair of beams 8 are also loaded so that they eachdeflect inwardly, toward one another until latch-plate 58 is locatedadjacent to latch-plate 54 with bore 56 a and bore 56 b overlapping oneanother. Once in this arrangement, a coupling rod, such as k-wire 60, isinserted through bores 56 a, 56 b, through-bore 18, and bores 36 a bore36 b, thereby coupling distal pair of beams 6 and proximal pair of beams8 in their respective optimally biased state. In some embodiments,k-wire 60 includes a proximal portion 63 that has a smaller diameterthan the distal portion of the k-wire thereby defining a shoulder 67 atthe transition 69 between diameters. Shoulder 67 is often sized so as toengage the outer surface of latch-plate 54 and thereby prevent k-wire 60from further travel into implant 2 beyond transition 69. In anotherembodiment shown in FIG. 9B, a k-wire 61 comprises a flexible tail 62that is terminated by a second k-wire 64. Flexible tail 62 may befashioned from woven, non-woven, knitted, braided or crochetedmaterials, any of which can included but not be limited to standardsurgical sutures, polymer or fiberous cords, metal wire or tape, or thelike, and may be formed from a single multiple strands of metals,polymers, or other bio compatible materials. Often, flexible tail 62comprises a metal braid or cable. K-wire 61 may have a circular, oval orflattened cross-sectional profile similar to that of K-wire 60 b (FIGS.20-23).

Implant 2 is used in systems and methods for corrective surgery at thedistal B, middle A, and proximal C phalanxes of the foot or elsewhere inbones of the human or animal body, as follows. The PIP joint is firstopened and debrided and an initial k-wire 75 (FIG. 5) is insertedthrough the axis of the middle phalanx A and out the distal end of thetoe. Initial k-wire 75 is then removed distally from the distal tip ofthe toe (FIGS. 5A and 6). Using a broach or similar instrument (notshown) a canal D is defined through distal and proximal portions of thePIP joint. Canal D extends for a distance into middle phalanx A alongthe path defined previously by k-wire 75 such that a counter-boreshoulder 71 is defined at the transition between the diameters of canalD and the passageway formed by the prior insertion of k-wire 75.Shoulder 71 is often sized so as to engage the outer surface of alatch-plate 54 or 34 and thereby prevent implant 2 from further distaltravel into middle phalanx A.

Once the surgical site has been prepared in the foregoing manner, animplant 2 that has been coupled to a k-wire 60 or 61 is inserted throughbroached canal D (FIGS. 7 and 7B) such that k-wire 60 travels throughmiddle phalanx A and distal phalanx B with distal end portion 63projecting outwardly from the end of distal phalanx B. In thealternative, flexible tail 62 travels through middle phalanx A anddistal phalanx B with distal end portion 63 projecting outwardly fromthe end of distal phalanx B. Flexible tail 62 may often be employed toease implantation. In one embodiment, a cord 62 provides the flexibilitythat is often needed by the surgeon to position the implant within thepatient's bone, while maintaining tensile strength for removing k-wire61 from the implant during deployment. In one embodiment, flexible tail62 and k-wire are left protruding from the patient's foot F by thesurgeon so as to allow the patient to slip on a shoe G or other footwear (FIG. 9E). Traditionally, a rigid k-wire was left protruding fromthe patient's toe by the surgeon, when the surgery was completed. Thisarrangement prevented the patient from wearing shoes which oftenprecluded the patient from returning to work based upon work placesafety regulations.

With either arrangement, implant 2 travels down the longitudinal axis ofmiddle phalanx A until the constrained distal beams 6 are adjacentshoulder 71 within broached canal D (FIG. 7). Once in position, endportions of distal pair of beams 6 are located adjacent to shoulder 71within middle phalanx A and proximal pair of beams 8 project outwardlyfrom the open end of canal D at the proximal end of middle phalanx A.Next, the joint is re-aligned and closed by moving the distal and middlephalanxes so that proximal pair of beams 8 is caused to enter the openend of canal D in proximal phalanx C (FIG. 8). In this position,proximal pair of beams 8 are located within canal D in proximal phalanxC and the joint is closed around implant 2.

Once in the foregoing arrangement, k-wire 60 is moved distally (FIG. 9)so as to disengage from latch-plates 54 and 58 of proximal beams 8thereby decoupling and releasing beams 44 and 46 from their optimallybiased state. Alternatively, k-wire 64 is moved distally (FIG. 8B and9C)) thereby pulling flexible tail 62 and k-wire 61 so as to disengagefrom latch-plates 54 and 58 of proximal beams 8 thereby decoupling andreleasing beams 44 and 46 from their optimally biased state. As aresult, superior beam 44 and inferior beam 46 spring outwardly, awayfrom one another, until their respective barbs 50 a and 50 b engage thesurface of the surrounding bone that defines broached canal D. Sincesuperior beam 44 and inferior beam 46 are still biased, i.e., continueto store some elastic energy, but are geometrically shortened by anamount 6. Barbs 50 a and 50 b compressively engage the surface of thesurrounding bone so as to “bite” into the bone, thus enhancing theretention of implant 2. It should be noted that the respectiveshortening of the moment arm of proximal pair of beams 8 applies anactive compressive force to articulating surfaces of the PIP joint.K-wire 60 continues to be decoupled and withdrawn from implant 2,through through-bore 18 of cannulated body 4 until distal end 70 slipspast through-bores 36 a, 36 b in latch-plates 34 and 38 of distal pairof beams 6 so as to entirely decouple k-wire 60 from implant 2 (FIG. 9).As a consequence, superior beam 24 and inferior beam 26 springoutwardly, away from one another and away from their optimally biasedstate into a partially biased state in which distal pair of beams 6engage the surface of the bone that defines broached canal D. Hereagain, it will be understood by those skilled in the art that ascantilevered distal pair of beams 6 move into their second partiallybiased state, they will also shorten. This geometric effect applies anactive compressive force to the articulating surfaces of the PIP jointwhile proximal pair of beams 8 maintain cortical fixation on either sideof the joint. Advantageously, barbs 30 a and barbs 30 b are caused tobite into the bone that defines broached canal D by the outward force ofsuperior beam 24 and inferior beam 26 moving into their partially biasedstate. The biting of barbs 30 a and 30 b into the bone greatly enhancesthe compressive load exerted by proximal pair of beams 8.

In an alternative embodiment illustrated in FIGS. 6A-9A, once thesurgical site has been prepared as described hereinabove, an implant 2that has been coupled to a k-wire 60 is inserted through broached canalD (FIG. 6A). In this way, implant 2 travels along the longitudinal axisof middle phalanx A until the constrained proximal beams 8 are adjacentthe end of broached canal D within proximal phalanx C (FIG. 7A). Once inposition, k-wire 60 is moved distally (FIG. 8A) so as to disengagedistal portion 63 from latch-plates 34 and 38 of proximal beams 8thereby decoupling and releasing beams 24 and 26 from their optimallybiased state. As a result, superior beam 24 and inferior beam 26 springoutwardly, away from one another, until their respective barbs 30 a and30 b engage the surface of the surrounding bone that defines broachedcanal D. Since superior beam 24 and inferior beam 26 are still biased,i.e., continue to store some elastic energy, but are geometricallyshortened by an amount δ, barbs 30 a and 30 b compressively engage thesurface of the surrounding bone so as to “bite” into the bone, thusenhancing the retention of implant 2. It should be noted that therespective shortening of the moment arm of proximal pair of beams 8applies an active compressive force to articulating surfaces of the PIPjoint while distal pair of beams 6 maintain cortical fixation via barbs30 a and 30 b.

With proximal pair of beams 8 fully seated within the proximal phalanxC, the joint is compressed axially so as to fully seat proximal pair ofbeams 8 within broached canal D (FIG. 8A). K-wire 60 continues to bedecoupled and withdrawn from implant 2, through through-bore 18 ofcannulated body 4 until proximal end 70 slips past through-bores 56 a,56 b in latch-plates 54 and 58 of distal pair of beams 6 so as toentirely decouple k-wire 60 from distal pair of beams 6 (FIG. 9A). As aconsequence, distal pair of beams 6 spring outwardly, away from oneanother and away from their optimally biased state into a partiallybiased state in which distal pair of beams 6 engage surface of the bonethat defines broached canal D. Here again, it will be understood bythose skilled in the art that as cantilevered distal pair of beams 6move into their second partially biased state, they will also shortentheir length. This geometric effect applies an active compressive forceto the articulating surfaces of the PIP joint while distal pair of beams6 maintain cortical fixation. Advantageously, barbs 50 a located on anouter surface 51 of superior beam 44 and barbs 50 b located on outersurface 52 of inferior beam 46 are caused to bite into the bone thatdefines broached canal D by the outward force of superior beam 44 andinferior beam 46 moving into their partially biased state. The biting ofbarbs 30 a, 30 b, 50 a and 50 b into the internal bone surfaces at bothsides of the joint, coupled with the geometric shortening of bothproximal beams 8 and distal beams 6, greatly enhances the compressiveload exerted across the PIP joint.

Numerous changes in the details of the embodiments disclosed herein willbe apparent to, and may be made by, persons of ordinary skill in the arthaving reference to the foregoing description. For example, andreferring to FIGS. 10-12, implant 82 is provided that includes a body84, a distal pair of cantilevered beams 86, and a proximal pair ofcantilevered beams 88. Unlike cannulated body 4 of implant 2, body 84defines an elongate, channel or groove 90 having a distal end 94 and aproximal end 95. Distal pair of beams 86 a, 86 b are arranged in spacedconfronting relation to one another at distal end 94 of body 84. Eachbeam 86 a, 86 b is fixed to distal end 94 and in some embodiments, isformed integral with body 84. One or more barbs 96 are located on anouter surface of each distal beam 86 a, 86 b. Open-ended groove 90extends through an inner portion of body 84. An open-ended groove 100 ais defined as a channel through an inner distal portion of distal beam86 b (FIG. 10) that is sized so as to slidingly receive a sharpenedportion of a k-wire 60 a. Distal pair of beams 86 a, 86 b arecantilevered to body 84, i.e., supported or clamped at one end andcapable of storing elastic energy when loaded or pre-loaded at the otherend or along their length. When distal pair of beams 86 a, 86 b arecoupled and loaded during normal use, they each deflect inwardly, towardone another.

Proximal pair of beams 88 a, 88 b are arranged in spaced confrontingrelation to one another at proximal end 95 of body 84. One or more barbs96 are located on an outer surface of each proximal beam 88 a, 88 b. Agroove 100 b is defined as a channel through an inner distal portion ofproximal beam 88 a (FIGS. 10 and 11) that is sized so as to slidinglyreceive a rounded portion of k-wire 60 b. As with distal pair of beams86 a,86 b, proximal pair of beams 88 a, 88 b are also cantilevered tocannulated body 84 but at proximal end 95, i.e., supported or clamped atone end and capable of storing elastic energy when loaded or pre-loadedat the other end or along their length. When proximal pair of beams 88a, 88 b are and coupled loaded during normal use, they each deflectinwardly, toward one another.

Implant 82 is prepared for use in corrective surgery at the distal B,middle A, and proximal C phalanxes of the foot in much the same way asimplant 2. More particularly, distal pair of beams 86 a, 86 b are loadedso that they each deflect inwardly, toward one another such thatopen-ended groove 90 of body 84 and groove 100 a are arranged insubstantially coaxial relation to one another. Likewise, proximal pairof beams 88 a, 88 b are also loaded so that they each deflect inwardly,toward one another such that open-ended groove 90 of body 84 and groove100 b are arranged in substantially coaxial relation to one another.Once in this arrangement, k-wire 60 a is inserted through groove 100 a,open-ended groove 90, and groove 100 b, thereby coupling distal pair ofbeams 86 a, 86 b and proximal pair of beams 88 a, 88 b in theirrespective optimally biased state.

As with implant 2, removal and decoupling of k-wire 60 causes distalpair of beams 86 a, 86 b and proximal pair of beams 88 a, 88 b to springoutwardly and away from one another thereby shortening their lengths soas to apply an active compressive force to the articulating surfaces ofthe PIP joint. Advantageously, barbs 96 are caused to bite compressivelyinto the bone that defines the broached canal by the force of distalpair of beams 86 a, 86 b and proximal pair of beams 88 a, 88 b movinginto their partially biased state as a result of the elastic energy thatcontinues to be stored in each beam. The biting of barbs 96 into thebone greatly enhances the compressive load exerted by implant 82. Whendistal pair of beams 86 a, 86 b and proximal pair of beams 88 a, 88 bspring outwardly and away from one another after the k-wire 60 is fullydecoupled, the elongate channel or groove 90 having a distal end 94 anda proximal end 95 is again able to slidingly receive k-wire 60. Thesharpened portion 60 a of k-wire 60 is, e.g., driven proximally throughthe tip of the patient's toe and through distal end 94 and proximal end95 of groove 90 of implant 82 to achieve temporary stabilization ofoutlying joints (e.g., the MTP joint).

Implants in accordance with the general principles of the invention maybe take a variety of configurations. Referring to FIGS. 13-17, aproximal beam 86 a and distal beam 88 b, may be arranged on theirrespective ends of body 84 with somewhat thinner or variablecross-sections so as to allow for adjustments in spring force to apredetermined level as may be needed for a particular therapy. Referringto FIGS. 18-19, it will be understood that implant 2 may incorporate aninferior latch-plate 38 a or 58 a located anywhere along the length ofits corresponding beam 26, 46. As shown in FIGS. 20-23, implant 2 mayhave any peripheral shape. Often, implant 2 will have a circular orelliptical peripheral shape so as to be better suited for dispositionthrough drilled canal D. It should be noted that with circular orelliptical embodiments of implant 2, bores 36 a, 36 b or 56 a, 56 b maybe defined with one or more partially flattened walls 110 so as to allowfor sufficient wall thickness in latch plate and for engagement with acorrespondingly shaped k-wire 60 b. This arrangement allows the surgeonto rotationally orient implant 2 relative to the bone surface thatdefines broached canal D. As shown in FIGS. 24 and 27, an implant 112may be formed so as to bend at or adjacent to the central portion ofbody 4 a. In these embodiments, distal pair of beams 6 or proximal pairof beams 8 may be arranged and oriented at an angle relative to body 4a. A similarly shaped k-wire also comprised of Nitinol to insert throughbend 60 c is coupled and decoupled during use of implant 112 in a mannerpreviously disclosed herein.

Turning now to FIGS. 28-29, an implant 122 is provided that includes abody 124, a distal cantilevered beam 126, and a proximal cantileveredbeam 128. Body 124 defines an through bore 130 and has a distal end 134and a proximal end 135. Proximal beam 126 projects longitudinallyoutwardly from distal end of body 124, while distal cantilevered beam128 projects longitudinally outwardly from the proximal end of body 124.One or more barbs 136 are located on an outer surface of each of distalend 134 and a proximal end 135. A latch-plate 140 extends inwardly froma free end of proximal cantilevered beam 126 and a second latch-plate142 extends inwardly from a free end of distal cantilevered beam 128. Abore 146 a is defined through latch-plate 140 and a bore 146 b isdefined through latch-plate 142. Cantilevered beams 124, 126 arecantilevered to body 124, i.e., supported or clamped at one end andcapable of storing elastic energy when loaded or pre-loaded at the otherend or along their length. When cantilevered beams 124, 126 are loadedduring normal use, they each deflect inwardly. Advantageously,cantilevered beams 124, 126 are arranged so as to be located diagonallyfrom one another relative to body 124.

Implant 122 is prepared for use in corrective surgery at the distal B,middle A, and proximal C phalanxes of the foot in much the same way asimplant 2. More particularly, proximal cantilevered beam 126 and distalcantilevered beam 128 are loaded so that they each deflect inwardly,toward the longitudinal axis of through bore 130 of body 124 so thatbore 146 a of latch-plate 140 and bore 146 b of latch-plate 142 arearranged in substantially coaxial relation to one another. Once in thisarrangement, k-wire 60 is inserted through bore 130, bore 146 a, andbore 146 b, thereby coupling distal cantilevered beam 126, and proximalcantilevered beam 128 in their respective optimally biased state.

As with other implant embodiments, decoupling of k-wire 60 causesproximal cantilevered beam 126 and distal cantilevered beam 128 tospring outwardly and away from one another and away from thelongitudinal axis of through bore 130 of body 124 thereby shorteningtheir lengths so as to apply an active compressive force to thearticulating surfaces of the PIP joint. Advantageously, barbs 96 arecaused to bite into the bone compressively by the outward force ofproximal cantilevered beam 126 and distal cantilevered beam 128shortening as they move into their respective partially biased state.The biting of barbs 96 into the internal bone surfaces at both sides ofthe joint, coupled with the geometric shortening of both proximal anddistal beams, greatly enhances the compressive load exerted by implant122 across the joint. Referring to FIGS. 30 and 31, it will beunderstood that an implant 122 a may be formed having distalcantilevered beam 126 a and proximal cantilevered beam 128 a that arearranged on the same side of body 124 rather than diagonally as inimplant 122.

Referring to FIGS. 32-36, implant 150 is provided that includes a body154 and a single pair of cantilevered beams 156 and a mating structuresuitable for joining implant 150 to a therapeutic device 157 viainterconnection with blind bores 151 a and 151 b defined in body 154.More particularly, single pair of cantilevered beams 156 comprise asuperior beam 160 and an inferior beam 162 arranged in spacedconfronting relation to one another at an end of body 154. Superior beam160 is fixed to an end of body 154, and in some embodiments, is formedintegral therewith. One or more barbs 96 are located on an outer surfaceof superior beam 160, often oriented transversely across the outersurface. A latch-plate 164 extends inwardly, toward inferior beam 162,from a free end of superior beam 160. A bore 166 is defined throughlatch-plate 164. Inferior beam 162 is fixed to an end of body 154, andin some embodiments, is formed integral therewith. One or more barbs 96are located on an outer surface of inferior beam 162, often orientedtransversely across the outer surface. A latch-plate 168 extendsinwardly, toward superior beam 160 and latch-plate 164, from a free endof inferior beam 162. A bore 170 is defined through latch-plate 168.Cantilevered beams 160, 162 are cantilevered to body 154, i.e.,supported or clamped at one end and capable of storing elastic energywhen loaded or pre-loaded at the other end or along their length. Whencantilevered beams 160, 162 are coupled and preloaded during normal use,they each deflect inwardly.

Implant 150 is prepared for use in surgery at a variety of orthopediclocations throughout a patient in much the same way as implant 2. Moreparticularly, single pair of beams 160, 162 are loaded so that they eachdeflect inwardly, toward one another such that bore 166, bore 170, andblind bore 151 b are arranged in substantially coaxial relation to oneanother. Once in this arrangement, k-wire 60 is inserted through bore166, bore 170, and blind bore 151 b, thereby coupling single pair ofbeams 160, 162 in their respective optimally biased state. As withimplant 2, decoupling of k-wire 60 causes single pair of beams 160, 162to spring outwardly and away from one another thereby shortening theirlengths so as to apply an active compressive force to the articulatingsurfaces of the PIP joint. Advantageously, barbs 96 are caused to biteinto the bone compressively by the outward force of pair of beams 160,162 shortening as they move into their respective partially biasedstate. The biting of barbs 96 into the bone greatly enhances thecompressive load exerted by implant 150.

Implants in accordance with the general principles of the foregoingembodiment of the invention may be take a variety of configurations.Referring to FIGS. 37-39, a tapered and ribbed anchor 173 may be coupledto body 154 via a threaded engagement between a post 175 and threadedbore 151 a. As shown in FIGS. 40-43, a suture anchor 178 may beassembled to body 154 in a similar manner to that of tapered and ribbedanchor 173. Bores 151 a and 151 b may be modified so as to communicate,via conduit 181 (FIGS. 40-43) thereby allowing suture 180 to exitimplant 150 near to single pair of beams 160, 162. Often, implant 150will have a circular or elliptical peripheral shape so as to be bettersuited for disposition through broached canal D. As shown in FIGS. 44and 49, implant 150 may be formed so as receive a threaded screw 200 orcannulated screw 210.

Although the invention has been described in terms of exemplaryembodiments, it is not limited thereto. Rather, the appended claimsshould be construed broadly, to include other variants and embodimentsof the invention, which may be made by those skilled in the art withoutdeparting from the scope and range of equivalents of the invention.

1-14. (canceled)
 15. An intramedullary implant system comprising: a bodyhaving an end from which project a pair of beams arranged about alongitudinal axis of said body, said beams each being fixed to said bodyand having an end, the end of one of said beams being releasably coupledto the other beam of the pair by a removable coupling rod, from one endof which projects a flexible tail, the beams each being deflectablebetween (i) a coupled and biased position for insertion of the beamsinto a respective bone with at least a portion of said flexible tailpositioned outside of a bone, and (ii) an uncoupled position forgripping said respective bone, said pair of beams in the uncoupledposition being arranged so as to form a compressive engagement with saidrespective bone.
 16. An intramedullary implant system according to claim15 wherein said beams each deflect inwardly toward said longitudinalaxis when coupled and biased by said removable coupling rod prior toinsertion into a respective bone.
 17. An intramedullary implant systemaccording to claim 16 wherein said beams are arranged symmetricallyabout said longitudinal axis of said body.
 18. An intramedullary implantsystem according to claim 16 wherein said beams are arrangedasymmetrically about said longitudinal axis of said body.
 19. Anintramedullary implant system according to claim 16 wherein said beamsare arranged in diagonally spaced relation to one another on said body.20. An intramedullary implant system comprising: a body defining athrough-bore along a longitudinal axis and having an end from whichproject a pair of beams arranged about a longitudinal axis of said body,said beams each being fixed to said body and having an end, the end ofone of said beams being releasably coupled to the other beam of the pairby a removable coupling rod, from one end of which projects a flexibletail the structure of which is selected from the group consisting ofwoven, non-woven, knitted, braided or crocheted strands, the beams eachbeing deflectable between (i) a coupled and biased position forinsertion of the beams into a respective bone with at least a portion ofsaid flexible tail positioned outside of a bone, and (ii) an uncoupledposition for gripping said respective bone, said pair of beams in theuncoupled position being arranged so as to form a compressive engagementwith said respective bone.